1/100k-64 if you trust config menu.
The values you can enter in the menu do tell you anything about the actual limits.
Generally all ports will work up to 64 seconds. Ones with "extended Tv" support will potentially go up to 2000 seconds. The limit for short exposures is much less well defined, but practically speaking you are unlikely to get 1/100k, and even if you could, you wouldn't find many subjects to use it on. Most ports that have been tested seem to do at least 1/20,000, although there may be a few that don't go over the factory limit.
